Monday, May 10, 2010

Results Of Energy Expenditure Poll

Expending more energy than we consume does not lead to long-term weight loss.

The collective wisdom from this poll is that expending more energy than we consume will lead to long-term weight loss.

This is contrary to what Gary Taubes wrote in his book, Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease.

Taubes said:

"Obesity is a disorder of excess fat accumulation, not overeating, and not sedentary behavior."

"Consuming excess calories does not cause [Taubes' emphasis] us to grow fatter, any more than it causes a child to grow taller. Expending more energy than we consume does not lead to long-term weight loss; it leads to hunger."

________

Painting, Vincent Van Gogh's Noon Rest From Work from irisms at Panoramio.

I disagree with the premise that consuming excess calories does not lead to weight gain. In my own experience if I want to lose weight I have to watch my caloric intake and increase my activity level. It works every time. I believe that Taubes' assertion was based on the fact that people ate more when they exercised thus leading to weight gain. The obesity problem in this country is from eating too much of bad food. Calorie counting works. It is hard work given the proliferation of prepared, refined calorie dense snack food. If you limit yourself to fruit and vegetables, with occasional meat or fish, sans fatty, sweetened dressings you easily lose weight. If you maintain your calorie intake and increase activity slightly you will lose weight.

As I see it, expending more energy than we consume will result in a loss of mass. So, I voted false to Taubes' statement.

However, I see his point.

Exercise/movement/physical activity is not the only way a human body can lose its mass. You can lose mass by:

- Losing a limb or other body part.- Urinating, defecating, vomiting. (This involves a loss of body cells, but also, e.g. a person with uncontrolled diabetes will lose glucose in their urine. That glucose possesses stored energy in its chemical bonds, calories if you will. So, a person with blood glucose over about 180 mg/dl may start losing weight.)

You can also lose mass by expending potential energy, that is, the energy stored in chemical bonds, by:

- Thinking (Brain cells, that is, nervous system cells, use about twice the energy in their cell functions as other cells)- Digesting food- Repairing tissue- Fighting bacteria, viruses, other microorganisms- Hundreds of other reactions that we don't feel, don't see, but that involve energy transfer

All of these losses or expenditures of energy (kinetic, potential) contribute to weight loss. But the interplay is complicated...

Each of us converts the energy in food to stored energy with different efficiencies. There are so many variables ... texture and temperature of food, molecular makeup of food (carb/fat/protein), quality and quantity of enzymes and hormones we release, quality and quantity of our absorptive cells, our nutrient status, the quantity and type of bacterial cells in our colon, the gradients between blood and GI tract cells. Gobs more things. Very complex.

When I get down to the reality of it, I'd say that what an average person eats has a bigger impact on their weight than how much they exercise, but exercise still matters.

Would people exercise less if they thought it wasn't going to help them lose weight? This is a tough call. I think people are more likely to exercise for the very tangible and desirable result of weight loss than for a result of, say, lymph movement or prevention of bone loss.

Good comment Bix. Unfortunately, I think you are right when it comes to exercise and motivation. I think most people are motivated to exercise because it is perceived as a weight management tool.

What's sad is that there are so many other excellent reasons to exercise. I would even argue there are better reasons: improved cognition and memory, antidepressant effects, increased energy, improved muscle and bone strength, and better sleep. Those are just a few. Thinking about them, it would seem like the benefits become more valuable the older you get.

I think it's best to understand the variables of your health not as a list but as a spider web. When one variable changes, everything else shifts to varying degrees. It's complicated.